The purpose of the proposed research is to examine critically selected parameters which are believed to be most relevant to the ultimate fate of the human patient with cancer. The current proposal describes the use of athymic (nude) mice as individualized in vivo assay systems for evaluating the effects of human tumor-bearing host cells and/or humoral factors on tumor growth. The growth of individual tumors is a necessary step in evaluating not only a particular individual's immune potentials, but also in determining the efficacy of various forms of therapy such as radiotherapy, chemotherapy, or immunotherapy in a particular host-tumor system. The overall objective of the proposed project is to provide a unique approach to individualized immunodiagnosis and immunotherapy of humans with cancer, through the use of athymic (nude) mice as in vivo assay systems for growth and manipulation of human tumors and human immune factors. These studies will help to define the immunological status of cancer patients and provide a framework for developing methods for immunological engineering, whereby immunization of individual cancer patients with either specific or non-specific forms of immunotherapy, in combination with other treatment modalities, will achieve the greatest benefit for the patient.